Concrete road finishing machine



Oct. 25, 1960 N. B. BEDERMAN ET AL 2,957,396

CONCRETE ROAD FINISHING MACHINE Filed Dec. 27, 1955 '7 Sheets-Sheet 1 l INVENTORS Q NATHAN a. azormwzr/ BY NOE/VAN V. JONES ArTo/e/var.

Oct. 25, 1960 N. B. BEDERMAN EIAL 2,957,396

CONCRETE ROAD FINISHING MACHINE 7 Sheets-Sheet 2 Filed Dec. 2'7, 1955 INVENTORS NATHAN 5. BEDEIZMA/V BY Nae/WAN M. JONES JrrazA/L'Y- Oct. 25, 1960 N. B. BEDERMAN ETAL 2,957,396

CONCRETE RCAD FINISHING MACHINE 7 Sheets-Sheet 3 Filed Dec. 27, 1955 INVENTORS NATHAN EEDEE/YA/Y m NOE/141V M JUNES .A TTOPNE Y.

Oct. 25, 1960 N. B. BEDERMAN ETAL 2,957,396

CONCRETE ROAD FINISHING MACHINE Filed Dec. 27, 1955 7 Sheets-Sheet 4 INVENTORS NATHAN l BE-P ENAIV 1:7 6. 5 VfE/VAN M. JONES Oct- 1960 N. B. BEDERMAN EIIAL v2,957,396

I v CONCRETE ROAD FINISHING MACHINE Filed Dec; 27, 1955 I 7 Sheets-Sheet 5 Fig. 8.

IN VEN TORS NATHAN B. BEO 'ENAIV yoeMA/v M. uo/vss WENEX Oct. 25, 1960 N. B. BEDERMAN ETAL 2, 7,

CONCRETE ROAD FINISHING MACHINE Filed Dec. 27,1955 I V 7 Sheets-Sheet 6 0 6 N4 THAN a. 550 8 NoeMA/v M. Jd

Oct. 1960 N. B. BEDERMAN ETAL 9 CONCRETE ROAD FINISHING MACHINE Filed Dec. 2'7, 1955 7 Sheets-Sheet 7 IN VEN TOR! N14 THA N l. JEDEEMA IV NORMA/V l7. JONES Unite 1. f

CONCRETE ROAD FINISHING MACHINE Filed Dec. 27, 1955, Ser. No. 555,326

Claims. (CI. 94-45) The present invention relates to road building machines and concerns itself with an apparatus that is adapted to be carried by the slip forms of a foregoing road processing machine such as a transverse screed paver, and to follow at a precise distance thereafter whilst executing under continuous and practically automatic manner a final longitudinal stroke finishing operation.

Although thus adapted, the present invention is de signed, nevertheless to be quickly severable from its host machine and to be independently maneuverable and transportable to and from work locations with but minor detachment and compacting operations. It embraces several utilitarian and economy advances over the art whereby to eliminate labor efforts and supervision in certain phases of its multiple purpose adaptability and thus attains the ultimate object of enabling the execution of high standard road building operations at lower cost.

It includes a nicely regulated crown curvature adjustment for its longitudinal troweling action which not only permits of an abundant range in crown radii and road widths, but also allows for practically any required transition rate of change as the machine progresses from straightaway road sections, where the maximum crown conditions are usually wanted, to road curves where totally flat conditions are the rule. During the reverse transitions the same or any other regulations may be elfected to suit any specification of road construction, all while maintaining the supporting carriage on a single sys tem of ways.

Provision is also made for optionally placing the screed carriage under automatically responsive control at ends of its travel, at both sides of the road, so that instead of the operators having to gauge the time of lifting the screed and reversing its work angle and direction of travel, a sequence of electrical limit switches each of which may be accurately and adjustably located in a sheltered path within the framework range of the ma chine, takes over the functions of first lifting, then changing the work angle and finally reversing the direction of travel of the screed carriage.

The invention also contemplates novel means of coupling and tandem machine integration whereby there. is attained a heretofore unknown degree of close tracking by a trailing road processing machine of its predecessor or foregoing apparatus which permits of the execution of subsequent road treating steps of a sequence with more accurate conformation in respect to the preceding ones, making the train of operations less susceptible to irregularities, chance factors or human error.

A principal object of the invention is to provide a piggyback type of road processing machine tandemvwhich will permit of the execution of a final finishing operation as by a longitudinally acting screed in trailing relationship to a foregoing machine such as a transversely acting screed machine in which the traction power of the foregoing machine is made to serve both its own and the trailing machines requirements.

Another object of this invention is to provide an atatent ice and have abundant strength to do its work so that its at tachment to a preceding machine may impose such insignificant additional draft burden that the normal traction power of the forerunning machine is able to carry both road processing machines.

Another object of the invention is to provide a road finishing machine of the character described in which a smoothing tool traveling from one side of the road to the other is carried upon a set of ways that may be flexed semi-automatically to a precise degree of curvature accuracy from a flat condition to conform with various ranges of crown forming requirements and yet permit of a progressive transition from the fiat to the maximum crown curvature and back again while the machine is in process of road finishing operations at whatever rate of change may be desired.

Another object of the invention is to provide in such a road crown curvature forming apparatus a processing tool support which at all times continues to be sustained by the same set of ways so that no discrepancy variations or disturbances in level are introduced besides the flexing adjustments inherent in the control regulation.

Still another object of the invention is to provide a support rail adjusting system in which the curvature angles across a total length of rail is effected simultaneously by a plurality of spaced fulcrum blocks each having its own system of progressive stepped levels and tensioning means for maintaining contact of the rail with its several blocks to insure constancy in its tangent relationship thereto.

Yet another object of the invention is to provide a system of switch controls for the screed lifting and screed carriage driving mechanism of a powered road finishing machine so that the carriage reversals at the ends of travel at each side of the road are executed automatically and at the precise locations without requiring attendance and human intervention at the completion of each transverse course.

The foregoing and other objects and purposes of the invention are such as will become more evident during the course of the following detailed descriptions and from the hereinafter annexed claims taken in conjunction with the accompanying drawings, in which like reference characters designate corresponding parts throughout, and in which:

Fig. l is a plan view with portions broken away of a road building slip form paving machine having embodied therein various features of the present invention;

Fig. 2 is a side elevational view of a machine such as illustrated in Fig. l simplified to accent the feature of the single flexible carriage supporting rail;

Fig. 3 is a side elevational view similar to Fig. 2 but on an enlarged scale and with intermediate sections broken out;

Fig. 4 is an enlarged longitudinal sectional view taken approximately on line 44 of Fig. l and with portions broken away featuring the screed lifting and powering mechanism;

Fig. 5 is an enlarged plan view of the machine frame and screed carriage structure;

Fig. 6 is a fragmentary sectional view through the screed carriage truck apparatus and is indicated by section lines 6-6 on Fig. 4;

Fig. 7 is a longitudinal sectional view with parts broken away through the screed lift mechanism and is indicated by section line 7-7 on Fig. 4; I

Fig. 8 is another enlarged side sectional view of the screed lift mechanism and it is indicated by section line 8-8 on Fig. 4;

Fig. 9 is a fragmentary plan view on an enlarged scale of one end of the screed mounting carriage featuring the end pivot studs and rail traveling truck mechanism;

Fig. is a perspective view on an enlarged scale of one of the stepped rail curvature control blocks and its appurtenant apparatus; Fig. 11 is a fragmentary sectional view taken approximately on line 1111 of Fig. 1 and features the manual regulating portion of one of the rail curvature control block systems;

Fig. 12 is a fragmentary sectional view similar to Fig. 11 but taken on line 12-12 of Fig. l and features the operating linkage which positions each of the rail curvature control blocks under the regulation of the manual slide bars such as shown in Fig. 10;

Fig. 13 is a side sectional view on an enlarged scale taken approximately on line 1.3-13 of Fig. 1 which features one of the corner legs and pneumatically operable transport wheels on which the road machine may be hauled to and from location;

Fig. 14 is a side elevational view of the structure shown in Fig. 13 as indicated by line 14-14 thereof but with various portions broken away to reveal posterior details, and

Fig. 15 is a plan sectional view on a further enlarged scale taken as indicated by line 15-15 of Fig. 14 and featuring the leg stabilizing wart projections and transport wheel operating mechanism.

The general framework of the machine, best observed from Figs. 1, 3 and 5, is substantially rectangular and although shown rigid, may include conventional severability at its primary side channel beams 21 and 22 to aid reduction in width so that shipment may be made under limits provided for by standard state commission regulations. These side channel beams 21 and 22 join with longer end channel beams 23 and 24 as by Welding or riveting and at the corners may be reinforced with gusset plates 25. Paralleling the end channels and spaced therefrom inwardly of the frame rectangle there are provided truck rail support channel 26 and 27 or I-beams which also may be secured to the framework at their ends by welding or riveting and to the corner gusset plates 25 in similar manner.

It is to be noted that the width of the frame is substantially greater than that of contemplated road widths, although in this connection too, enlargement or contraction is conventionally feasible without interfering with the structural plan and operation of the machine, it being necessary but to provide requisite lengths of rail for the screed trucks to suit need or specification.

Under proposed efficiencies of operation, the present invention contemplates being used as an adjunct to a preceding road machine, such as a transversely reciprocating screed or so called finisher equipped with slip form channel rail elements 28 and 29, see also Fig. 13. These slip forms are of the same height or depth as the pavement fringe and usually comprise a narrow top flange 31 and relatively wide bottom flange 32, the flange portions of the two rails being outward and the bottom flanges 32 serving as skids upon which the rails glide as the pavement is first deposited by preceding equipment and then worked into place and finished for smoothness. The preceding machine is advanced by suitable traction means which tread the strip areas flanking the roadway, at a slow but steady rate as the paving process thereof progresses and the length of the so called slip forms is enough to assure abundantly that the pavement takes a suflicient set to avoid shifting and collapse when the slip forms pass onwardly and lateral support is thereby withdrawn.

Whereas, in prior slip form machines means had to be provided for bridging across the trailing forms with some structural members which would hold them securely in spaced relationship to one another, the present machine riding astride these members in piggy-back fashion may now be relied upon to also contribute what retaining strength is needed for this purpose. Accordingly, at each corner of the present machine there is provided a perpendicularly extending leg 33, which may be formed of mutually facing channels with meeting flanges welded together to form box beam elements, Fig. 15, secured at their tops as by welding to the rail supporting I-beams 26 and 27. The distance between the pairs of legs 33 widthwise is in correspondence to that between the outermost edges of the top flanges 31 of the slip forms, so that when the present machine frame is set down, as will be explained later, integrating the host machine with its passenger machine into a substantially rigid combination of the two, the rails or slip forms 28 and 29 will hold their mutual spacing dependably.

The lowermost ends of the legs 33, see Figs. 13 and 15, affording rectangular openings are made to fit over upstanding wart projections 34 of suitable size and cluster arrangement to be snugly therein received. These projections are welded additions to the slip forms as are also the individual securing yokes 35, of which one is provided for each leg, being pivoted in pintle shafts 36 carried by weld lugs 37 made fast to the top surface of the forms at precise locations. After the passenger machine is wheeled into position for coupling with its host, the wheels are retracted by exhausting the pneumatic cylinders 38, causing them to retract their pistons 39, and thereby raising the wheel axle trucks 41, resulting in the shifting of the position of the wheels 42 from that shown in solid outline in Figs. 13 and 14 to that shown in dotted outline in Fig. 14.

As a consequence, the legs will settle down onto their wart projections 34 and the yokes 35 may then be swung from their dotted outline (Fig. 13) condition to their solid outline one. The wheels will now be out of range of contact with the roadbed side lanes and the host machine in full control over conveying the longitudinal screed apparatus whose functions will now be described. To assure additionally that the wheels 42 are clear of the road surface, the wheel assembly may include an outer frame 43 which straddles the leg 33 and the cylinder 38 may be pivotally hung as at 44, enabling the assembly to be swung clockwise, as viewed in Fig. 13 to a poised position (not shown) with its wheel 42 amply clear of engagement with the road surface.

In keeping with well recognized requirements of State and Federal standards of construction and road building specifications pertaining to smoothness, road surface finishing in particular respect to longitudinal regularity, is of increasingly greater importance today because of the speedsat which travel is becoming accustomed by private as well as commercial users. Small ripples or even shallow irregularities in grade transition which might escape visual detection may be the cause of producing bumps at high speeds. Longitudinal finishing is therefore of prime importance to safety, and the machines for accomplishing this degree of road finishing completion without unduly burdening the ultimate cost of the public improvement are most likely to find acceptance on a competitive basis.

The described finishing operation is one which has been found to be most effectively executed by reciprocating a suitably weighted trowel element or screed lengthwise of the road pavement to and fro while it is bodily advanced at a slower rate, from one side of the roadway to the other. While this is going on, an accumulation of surplus cement or grout is being advanced by the forward edge of the trowel or screed during one direction of travel, but on the reverse route of travel, to keep from discharging this accumulation over the slip forms, it must be encountered on the opposite side and pushed back by the screed before it reaches the extreme other side of the road. In order to assure that the accumulation is always kept foremost and not allowed to slip behind the screed tool'as it makes its alternate courses of travel, the screed is preferably inclined from perpendicularity with the road at a slight angle after the manner shown in Figs. 1 and 5, and this inclination is reversed for opposite directions of travel of the screed, for the manifest reason that in this way the accumulation is propelled forward aswell as sideward by the reciprocating action of the tool.

In Figs. 1 and 5 this inclination from the true longitudinal of the road has been best portrayed by showing the screed carrying carriage, generally designated 45, in both of its alternative slant conditions together with its screed element 46. The reciprocating motion of the screed is parallel to its own longitude so that as itmoves bodily across the width of the road, first in one direction, then in the opposite one, meanwhile the entire machine creeping forward steadily, there takes place concurrently a troweling or smoothing action of the surface of the road and a pushing primarily sideward but also significantly forward of the excess grout or cement accumulation by the sidewall surfaces of the screed element. This troweling action of the screed is effective, moreover, in making the roadbed either flat, across the width, or crowned in variable degree of curvature, by the provision of travel ways for the screed carriage which have corresponding curvature in adjustable degree. Also it will be noted that the screed is arrested in its sidewise progress just before it reaches each slip form, and is then lifted and reversed in slant and set down again to take up its travel in the opposite direction. This automatic control is effective to prevent the surplus grout accumulation from being pushed off the edge of the forms and instead be taken over the return course by the other side of the screed and pushed back toward the opposite side of the road. Thereby, paving material is conservevd more efiiciently rather than as where through occasional neglect or oversight, become wasted by discharge onto the side lanes.

The screed carriage 45 has at each end a main pivot stud 47, see also Figs. 4 and 6, which juts vertically from the floor 48 of each of its opposite end trucks 49. These are loose fitted journally so as to permit for shift movement as the carriage is reversed at the ends of its travel. Each truck 49, see also Fig. 9, is provided with a set of four wheels 51, 52, 53, and 54, preferably of the single flange type, of which the extreme ones 51 and 54 ride the outermost edge of their rail 5-6 or 57, Fig. 1, while the mean ones 52 and 53 ride the innermost edge thereof. In this way ample stability is afforded to the carriage throughout all of its possible conditions respecting slant of its direction as well as curvature variation in its track ways or rails 56 and 57. Each truck 49 is provided with axle supporting lugs 58 which bear the individual axles 59, one for each wheel as best shown in Fig. 9, as well as with end thrust bearings 61, Fig. 6, for easing the slant shift operation.

In addition, the screed carriage supports at each end a power'arm in the form of a triangular plate 62, Figs. 4 and 7, of which the lowermost portion is horizontal as at 63, terminating with a pivotal attachment 64 to its related one of a pair of endless side movement powering chains 65 and 66. Each of the power chains 65 and 66 is driven by its individual motor and speed reduction unit, generally designated 67 or 68, Fig. 1, under control of a system of start and stop switches which will ,be reviewed in more detail later. The points at which the portions 63 are articulated to their respective power chains are significant because thereby is regulated the slant angle of the carriage as well as the instants toward the end of travel in each direction, when the screed is lifted preparatory to slant reversal. When, for example, the carriage happens to be approaching the left side slip form 28, as viewed in Fig. 1, portion 63, on its power arm 62 encounters a control switch 69, Figs. 1 and 4, the electrical power is established for operating a pneumatic cylinder 71, causing it to eject its piston 72, and rotate equalizer bar 73 counterclockwise as observed in Fig. 4, and send its link bars 74 and 75 outwardly. Thev latter each rotates a bellcrank 76, pivoted at 77, causing to ,be lifted a roller truck assembly 78 guided in its channel housing 79.

As a consequence there are-raised the :free ends v81 of third class levers 82 which are pendulously supported from turnbuckle adjustable hangers 83 as at 84; This lift stroke initiated by pneumatic 71 causes roller 85 to become elevated sufficiently at each end .of the carriage to lift its shroud 86 thereby. Because the shrouds are integralwith the screed channel members 87 there results the parallel lifting of the screed 46 to a height sufiicient to clear the normal accumulation of grout in advance of the screed action.

In Fig. 1 are shown the location of various switches 69, 36 and 89 on one side (to the left of the observer) of the machine, which function to regulate the progress of the screed carriage 45. A similar arrangement of switches is employed at the right side of the machine, where they are illustrated but not designated by reference numerals. The operation of these switches is as follows: Let it be assumed that the screed carriage 45 is moving from right to left at the instant in which it is shown in Fig. 1. While this condition prevails, the screed proper 46 continues to reciprocate, to and fro along its own length, while because of its can-t or inclination, as shown in Fig. l, the paving material accumulations, collected by the regular action of the screed, are continually thrust leftwardly and forwardly. This keeps the accumulations adjacent the front end of the screed at its advancing edge or side.

Presently, the horizontal portion 63 of the lowermost triangular plate 62, encounters switch 69, see also Figs. 4 and 7, and as a result a contact pair thereat is closed completing a circuit which operates a fluid pressure cylinder 71. This raises the screed 46 so that it then becomes disposed above the quantity of grout or other paving material accumulations acted upon by the screed, and as a consequence enables the screed to be brought over and then around to the other side of the accumulations, in readiness for the return movement to the other side of the road.

Meanwhile, screed carriage 45, still moving leftward under the impetus of both its driving chains 65 and 66, arrives at a point whereat its triangular plate 62, having operated switch 69, as above explained, next engages and operates switch 88. This results in the opening of an operating circuit for driving motor 68 in one direction, which has been impelling carriage 45 leftwardly, and instead prepares a circuit for operating motor 68 in the opposite direction. As a consequence, the bottom end of the carriage 45 stops moving, but the top end continues leftwardly until the entire carriage acquires a condition such as that shown by the dotted outline on the left side of Fig. 1. When this occurs, the triangular plate 62 at the top of the carriage 45 engages and operates a switch that produces four significant results.

First, it opens the circuit which until then has been operating electric motor 67 to impel the top of carriage 45 leftwardly. Also, it prepares a circuit for enabling the reverse rotation of motor 67, completes a circuit, previously prepared, for operating motor 68 for rightwardly propelling carriage 45, and it releases cylinder 71 allowing screed 46 to descend. Thereupon, carriage 45 moves to the right assuming a cant or slope such as that designated by the dotted outlines in Fig. 1, while the reciprocating screed 46, now on the other side of the surface accumulations of paving material, pushes such material rightwardly and again forwardly.

At the right of the machine, a similar series of electrical switches to those designated 69, 88 and 89 on the left side, operates to perform the sequence of movements necessary to lift the screed and reverse the carriage 45 for return travel.

The screed itself may at all times continue to reciprocate, as has been said, moving in its own plane to and fro impelled by the link bar 91 which has a ball articulation with the screed channel 87 as at 92, Fig. 4, and another with a crankarm 93 as at 94. Crankarm 93 is part of a rotor member $5 which receives its power through a shaft 96 from a gear reduction unit 97, driven'by a motor 98. The just described motor and gear reduction combination 98-97 is carried on a platform 99 at one end of the carriage, and another such platform 101 at a somewhat lower level is provided for the purpose of supporting a standing operator who may travel with the carriage to oversee the adequacy of the work accomplished.

The to and fro motion of the screed is constrained by a system of guide rollers mounted in a stabilizing frame 102, Fig. 8, disposed in each of the two shrouds 86 at opposite correspondingly spaced points respecting the screed. These frames 102 are pendulously supported from the center or work roller 85 of levers 82 and stabilized by auxiliary arms 103, forming a parallelogram with the free arms of levers 82. Also the frames 102 provide shaft ears 104 for carrying the shaft 105 of horizontal roller 85 and others 106 for carrying the shafts 107 of side sway stabilizing vertical rollers 108, one on each side of the frames 102.

It has been explained that the carriage trucks 49 ride upon roller wheels 51-54 which in turn ride upon rails 56 and 57. These rails are indicated as inverted channel members disposed over their supporting I-beams 26 and 27. Attention is now directed to Figs. 1-3 and -12 where appears the disclosure of apparatus for imparting, by flexing, variable degrees of curvature to the rails 26 and 27 to establish the crown or drainage curvature which is preferred at certain parts of a roadway system.

This crown effect is not desirable throughout the entire road, nor is the same degree of curvature wanted for all roads, because of various factors which road building engineers recognize to be susceptible to local conditions. Principally, straightaway sections of a highway are wanted to have the full benefit of crown curvature while turns in the highway are wanted to have quite flat cross-sections. It thus presents to the road finisher who is to perform the longitudinal floating or troweling operation the problem of affording to straightaway sections their curved characteristic and to turns, the flat characteristic. Also it is required to execute between the two described classes of section a sufiiciently gradual transition to avoid the possible consequence of bumps to high speed driving.

Accordingly, there is proposed a system of ways which comprise full width transversely extending inverted channels 56 and 57 which, as revealed in Fig. 10, preferably have one short web 111 and a long one 112. At spaced; intervals along the length of the rails there are provided pneumatic actuators such as designated 113, 114, 115, and 116. The central actuator 113 may have its piston terminal pivotally secured to cars 117 which are secured to the rails (Fig. 3), while the other actuators may have their piston extremities pivotally secured to similar ears which are mounted in a suitable manner to permit a lateral shifting to a slight extent with respect to the rails. This is to accommodate for the displacement which takes place in the length of the rails during their curvature changes.

Each pneumatic cylinder 113-116 is flanked by a pair of limit stops, which are adjustment rods 121 threaded and provided with double stop nuts 122 so that the extent to which the rail section adjacent each pair of limit stops may be thrust by the pneumatic actuator is in this manner precisely established. In practice, the adjustments of the several pairs of limit stops is so made that when actuating fluid is introduced into the several piston chambers of the cylinders 113-116 simultaneously, the rail will be arched into a curve somewhat in excess of the maximum required and then upon release is permitted to return to a precise degree of are as determined by the stepped blocks 127.

Actually the degree of flexure to which the rail metal becomes subjected is but slight so that ordinary cold rolled stock may be used for this purpose and replaced periodically if worn. Such stock material is able to withstand long use before becoming worn or brittle from repeated flexing. At the endmost points the rails 56 and 57 are provided with elongated apertures 123, Fig. 3, in each of which is received a bolt or pin 124, anchored in the triangular supports 125. The latter are secured to the top flanges of the frame beams 26 and gusset plates 25 with intervening shims 126 to afford additional regulation and adjustment for achieving accuracy in respect to height at the roadway sides. From the foregoing it will appear that by actuating the neumatics simultaneously first in the lifting direction then in the lowering direction the rails 56 and 57 may be brought down to precise settings instantly and semi-automatically which settings the correct curvatures of the rail top surface can be attained.

The return of the rails to their down positions is established by stop elements in the form of stepped blocks 127, Figs. 6 and 10-12, mounted on side rollers 128 which are confined in guide chanels 129 and 131. Each block 127 of which there are a series relating to each rail 56 and 57 has a certain number of stepped levels, the number of which corresponds to the number of adjustments arbitrarily allotted to the manual adjustment system which will now be explained. Obviously, all of the blocks 127 comprising a set, and which are disposed spacedly across the width of the machine, are not identical step-for-step. Instead, the height of the steps at each alignment varies in such a manner as to form plotting points of a different curvature and these are imparted to the rails 56.

At one end of the machine frame, preferably on one of the gusset plates 25 there is located a slide bar 132, Figs. 11 and 12, having notches 133 adapted to be retained by a limit lug 134 in one or another of its several series positions. These positions correspond in number and spacing to the stepped levels of the blocks 127, so that by shifting the slide bars 132 from one extremity to another one step at a time during the interim between the aforedescribed raising and lowering pneumatic actuations of the rail members 56 and 57, there may be brought about the establishment of the rail curvatures in successive steps or degrees. In other words, the attendant operator will grasp the handle 135 of first one bar 132 on one side of the machine and move it across one notch distance in terms of stop or limit lug 134 and then he will move the other bar 132 on the other side of the machine and likewise move it through one notch distance. In this way, depending on the direction in which he moves the bar 132, he will elfect a gradual change incrementally in the curvature of the rails 56 and 57 between maximum curvature and absolute flat, or vice versa.

The movement of the bars 132, through their connection with links 137, Fig. 11, effects rocking of master arms 138, and through them of shafts 139. Rocking of shafts 139 results in the corresponding movement of individual block arms 141, which in turn shifts all of the blocks 127. Following this the pneumatics 113-116 realign all of the rail projections 142, Fig. 10, to seek intimate contact with the particular ones of the block steps of their respective blocks 127, and a new curvature is established in accordance with the different levels of each row of steps in the blocks 127.

It will be recalled that these changes respecting the degree of crown curvature to be made on the roadbed customarily are involved only at the times that a turn Lil] the highway is being approached or just after one is being withdrawn from. Consequently, the transition involves the making of a slight pitch angle in certain portions longitudinally of the the roadway which will be downhill at approaches to turns and uphill at recessions therefrom. In keeping with this condition, it is usually desirable to impart a corresponding longitudinal tilt to the screed as it is undergoing the interim transitions and toward this end the instant apparatus permits the operator to make the gauge block 127 adjustments respecting opposite sides of the machine with such difierential lag of one side behind the other that the carriage, and conse- 9 "quently its screed, will assume a slope in conformity with the desired tilt.

In practice the operator will manipulate the adjustment bars 132 only after the machine reaches one side of the road or the other, at which time it is an easy matter to reach over from his position on the platform 101, or if attending the operation from the side strips, to grasp these controls within easy reach therefrom. The pattern of the blocks 127 in respect to its stepped sequence may also be so modified that where the road building authorities may wish to have more or less of elliptical curvature instead of simple arcuate radius ones or still other cross-sections, the institution of the same is a mere matter of substitution of a suitable sytem of stepped blocks. This latitude together with the nice adjustment aflorded by the shim regulation 126 at the end support plates 125 permits the user of the present machine to accomplish precision heretofore unknown in road finishing.

Having thus described the invention, what is new and for which it is desired to secure Letters Patent in the USA. is set forth in the claims following:

1. In a roadway cement finishing machine, a main frame of width to span a roadway, said frame including a pair of transverse truck rail support channels, a pair of truck rails each located above one of said channels, a carriage having a wheeled truck at each of its ends adapted to ride one of said truck rails, power means for moving said carriage from side to side on said truck rails, a finishing tool carried by said carriage, power driven means borne by said carriage for reciprocating said finishing tool, a series of spaced projections extending downwardly from said truck rails, a corresponding series of stepped blocks supported on each of said channels, the successive steps of which define progressively varying degrees of arch curvature, means connecting the blocks of each series and for moving them in unison to cause them to present difierent ones of their steps beneath their related truck rail projections, and pneumatic means for flexing said truck rails into an arch and thereby raising their projections to afford clearance for permitting the operation of said block series connecting means to alter the disposition of said stepped blocks and for lowering said projections to permit them to engage the steps of said blocks.

2. A roadway finishing machine which comprises a rectangular frame adapted to span a roadway having a pair of spaced beams operatively disposed transverse of the rectangular frame, a series of spaced blocks each having a number of descending-level steps on each of said beams the corresponding steps of each series of said blocks compositely profiling a difierent degree of curvature arch, means for moving all of the blocks of a series in unison to cause them to present corresponding ones of their steps in a transverse alignment, a carriage supporting rail carried on each of said spaced beams and having a series of projections which extend downwardly each over a related one of said blocks, a plurality of double-acting fluid actuators associated with said rail for first flexing said rail into an arch sufficient to clear the stepped blocks and then restoring its rail to an extent determined by the encounter of the rails projections with the aligned steps of said blocks, and a screed carriage including a wheeled truck at each of its ends for riding one of said rails whereby to impart to said carriage an arched course of travel effecting a crown contour to a road surface as a finishing operation.

3. The combination set forth in claim 2 including power-driven endless chain means supported in each of said spaced beams, reversible drive motors for each of said chain means, arms at each end of said screed carriage articulated at predetermined points with their corresponding chain means, and control switches at predetermined points along the path of said chain means actuated by said screed carriage during its movement 10 transversely of the roadway to cause one of said chain means to start its movement ahead of the other in both directions of progress whereby to impart a slant from perpendicularity to said carriage and its screed for the purpose of propelling surface accumulations of paving material forwardly as well as sidewardly.

4. In a roadway finishing machine, a main frame extending across the width of a roadway, a pair of transversely extending parallel rails predeterminedly spaced from each other and supported upon said main frame, means for anchoring said rails in horizontal pivots at the ends of said main frame, a plurality of fluid actuators each including a cylinder and a piston arranged in vertical alignment, said actuators being spaced from each other for thereat exerting forces upwardly against their rails to flex them into a maximum arch curvature, a series of stepped blocks also arranged in spaced alignment beneath each rail for retaining said rail in various intermediate arch curvatures after said fluid actuator forces are released, each including a series of successively descending stepped surfaces and the corresponding surfaces of each series combinedly plotting different arch curvatures in accordance with their surface levels, means for shifting all of said stepped blocks of a series concurrently while said rails are flexed at their maximum arched curvature to interpose corresponding ones of their stepped surfaces beneath their rails for thereby varying the arched curvatures imparted to said rails, and a screed mechanism supported on said rails including powered means for advancing said screed mechanism from one side of a roadway to the other.

5. In combination with a roadway processing host machine which includes a self-traction mechanism having a pair of slip form rail elements each bearing a set of projections, a portable roadway finishing machine adapted to trail behind and be propelled by said host machine which includes, a substantially rectangular frame of suflicient width to straddle a roadway, a downwardly extending leg at each corner of said frame in alignment with and positionable on said projection of said slip form rail elements of said host machine, a wheel and axle truck therefor mounted on each of said legs upon which said portable machine may be rolled to and from location in respect to its said host machine, and means for retracting each of said axle trucks together with its wheel along its associated leg to thereby impose its leg over a related one of said projections home by its rail element.

6. In a roadway cement finishing machine for tandem coupling which comprises, a horizontal support frame including a pair of side channel beams each adapted to be disposed parallel to the roadway, a pair of end channel beams secured to and forming a rectangle with said side channel beams, a pair of truck rails each parallel to and located above a related one of said end channel beams and pivotally secured at its ends, a series of perpendicularly disposed fluid actuators beneath each of said truck rails and each including a piston, a piston rod and a housing, with the related piston rods directed upwardly, whereby during actuation of said series of fluid actuators the related truck rail is sprung into a maximum arched curvature, and a series of multiple-stepped blocks of which the corresponding steps are so proportioned as to impart a different one of a progressive series of crowned curvatures, means for shifting said blocks simultaneously into different positions for disposing corresponding ones of their steps beneath their related truck rails whereby to allow said rails to return to a lesser crown curvature of said series determined by the particular alignment of block steps thus positioned.

7. The combination set forth in claim 6 including a carriage supporting a power driven screed, said carriage comprising a pair of wheeled trucks, one pivotally connected to each end of the carriage, the wheels of said trucks being flanged and of opposed pairs, whereby to '11 confine the truck rail therebetween, and an endless power driven chain supported at each end of said horizontal frame for imparting driving motion to its related wheeled truck and therethrough to said carriage.

8. A roadway cement finishing machine for tandem coupling to a host machine which is adapted to span the width of a roadway and which is provided with a pair of trailing support forms having predeterminedly spaced locating projections comprising; a rectangular frame also adapted to span the width of a roadway, a rigid downwardly extending leg carried at each corner of said frame having portions adapted to engage the locating projections of said host machine trailing forms, a wheeled truck associated with each of said rigid legs and shiftable in respect thereto between a lowermost and roadway surface engaging position and an uppermost retractile position, and fluid operated power means for shifting said wheeled trucks between their said lowermost and uppermost positions for thereby elfecting the coupling engagement and disengagement respectively between said rigid legs and said host machine support forms.

9. The combination set forth in claim 8 in which said wheeled trucks and said fluid operated power means are pivotally mounted adjacent their associated rigid legs whereby they may be swung about the pivot clear of engagement with their legs during the time that said finishing machine is coupled to a host machine.

10. A roadway finishing machine which comprises; a main frame adapted to span the width of a roadway, a pair of horizontal rails one at each end of and supported by said main frame and also adapted to span the roadway, a carriage adapted to travel from one side of the roadway to the other supported at its ends by said pair of horizontal rails, a screed supported by said carriage for longitudinal oscillatory movement, a power mechanism borne by said carriage for oscillating said screed, and means for flexing said pair of horizontal rails into various arch curvatures for thereby efiecting corresponding crown curvatures in the transverse contour of a roadway, which includes for each said pair of horizontal rails a series of fluid operated piston and cylinder actuators for elevating the rails to a maximum degree, a series of stepped blocks and means for moving said blocks in unison throughout a sequence of placements for presenting at each of said placements a transverse alignment of their steps for engagement by said rails for thereby imparting to said rails a characteristic arch curvature when said fluid actuators descend from their elevated conditions.

References Cited in the file of this patent UNITED STATES PATENTS 2,073,998 Raby Mar. 16, 1937 2,084,068 Vinton June 15, 1937 2,235,105 Heltzel Mar, 18, 1941 2,299,700 Milliken et a1. Oct. 20, 1942 2,603,132 Miller July 15, 1952 2,650,525 Jones Sept. 1, 1953 2,779,258 Johnson Jan. 29, 1957 

